turbo lag in 3rd and 4th

[gavsgti]

hi there having proberlems with the boost on my agu 1.8t

it seems to boost fine in 1st but when i go 3rd and 4th it seems to boost then it seems to drop then pick up again bit like when a clutch is slipping? this also happens in second but not that often
ive changed the air filter and put a after market dump valve could t maybe that it needs remapping to set it up for these or maybe i have put the wrong spring in
the car was supposedly remapped before i bought the car but have no proof of this it was just what the previous owner had told me
i am going to get it remapped again  when i get chance to fit fmic, exhaust with sports cat which ive bought but need to find a back box so would this maybe cure the proberlem?
sorry if this has been posted before but ive searched on the search bar and couldnt find any answers
thanks in advance
gav

[WadGTI]

Swap to a oem divertor if you can to rule the dump valve out.

My mate has an aum and pretty much does the same thing, but this due to the a leak in the brake booster that he refuses to fix. Worth checking for vac leaks whilst your at it.

[mikej20vt]

My AUM was doing this mate in all gears but I had a Bailey's dump valve on from the previous owner. I've now put it back to the original diverter valve & it feels so much better & a hell of a lot more responsive.

[Mr_Orange]

I recall a dodgy engine speed / crank sensor can do this.

[Dalo Harkin]

I recall a dodgy engine speed / crank sensor can do this.

the most common thing for this going is the engine stalling when it gets to temp, its happened to mine before lol

[Dalo Harkin]

If you want to check if the clutch is slipping come to a stop, put it in 2nd and then completely lift your foot off the clutch, if its ok it'll cut out if not the clutch is slipping. (leave yourself a good 5 metres in front just in case  )

You can also approach a hill doing around 30mph, put it in 5th and then floor it, you'll know if it slips...

[Mr_Orange]

I recall a dodgy engine speed / crank sensor can do this.

the most common thing for this going is the engine stalling when it gets to temp, its happened to mine before lol

Agreed but mine threw a fault code for the sensor, changed it and fixed bad flat spot it had when booting it. Easy fix too.

[Tezmax]

I would say 95% vac leak.

Check ur pipes and connectors...then check them again

N249 valve delete can help remove degrading pipe work.

[viperjsy]

he has an agu so dose not have N249 valve delete